As a nanoporous membrane can separate nano-sized particles by size using a nano-sized pore, it is a future critical element that can be used in various fields such as a medical appliance, food and environment.
Most of the conventional nanoporous membranes were manufactured using polymer substances. The conventional nanoporous membranes had a highly complex structure and were greatly thick, which resulted in low selectivity and low permeability. Recently, in order to resolve these problems, efforts to manufacture a nanoporous membrane, which has a straight nanochannel and is thin, are actively being made using a micro machining technology.
The conventional methods for manufacturing a nanoporous membrane using the micro machining technology can be classified into: a method of forming a nano-sized pore by a specific type of chemical etching method, such as anodizing or ion-track etching, on a thin film formed on a substrate; a method of forming a nano-sized pore using a carbon nanotube as a mold; and a method of forming a nano-sized pore using an ion beam of high energy.
However, the above methods of forming a nanopore cannot be commonly used. Thus, they are difficult to be reproduced. Moreover, scaling up is difficult because those methods were prepared by using equipment generally designed and manufactured at laboratory level. Additionally, the method of using an ion beam of high energy is labor intensive in process, which requires high process costs.